• Preheat oven to 325°F. Position oven rack in the center of the oven.
• Cream butter and sugar in a large bowl with a hand mixer or in the bowl of a stand mixer using the paddle attachment until light and fluffy, about 3 minutes.
  2 ½ cups granulated sugar, 1 ¼ cups salted butter
• Add in room temperature eggs, one at a time, followed by extracts, mixing well after each addition.
  5 large large eggs, 2 teaspoon pure vanilla extract, ½ teaspoon butter extract, ½ teaspoon rum extract
• Whisk together cake flour and baking soda in a medium bowl.
  2 ½ cups cake flour, ¼ teaspoon baking soda
• Fold in ⅓ of flour mixture until just combined, followed by ½ of sour cream, and repeat until you finish up by folding in the last third of the flour mixture. Mix gently just until flour is incorporated.
  1 cup full-fat sour cream
• Brush cake release (cake goop) all over inside of the pan, being sure to get it in the crevices.
  cake release spread
• Spoon cake batter evenly into prepared pan. Tap pan firmly on the counter to eliminate air bubbles (you should see a few bubbles come to the surface).
• Bake in preheated oven for 60-75 minutes, or until a toothpick entered into the center of the cake comes out clean, or an instant-read thermometer in the center of the cake reads 210℉. While cake is baking, prepare caramel syrup.

Caramel Syrup and Glaze

• Mix together sugar and ¼ cup water in a small saucepan. Cook over medium heat, without stirring, until mixture turns a deep amber color.
  1 cup granulated sugar, ½ cup water
• Add in cubed butter and stir until melted and combined.
  ½ cup salted butter
• Stir in another ¼ cup water and evaporated milk and cook, stirring, over low heat another 2-3 minutes. Mixture should have a syrupy consistency. Stir in vanilla and rum extract and a pinch of salt to taste.
  ½ cup water, ¼ cup evaporated milk, 1 teaspoon pure vanilla extract, ¼ teaspoon rum extract, pinch salt
• Once cake is done baking, remove from oven and use a toothpick to poke holes all over the top of the cake in the pan. Pour ½ cup of syrup all over the top of the cake.
• Let cake cool in the pan for an hour, then flip out onto a wire rack to cool completely.
• While cake is cooling, bring remaining caramel syrup to a boil. Reduce heat to medium-low and cook another 5 minutes or until thickened, stirring constantly.
• Pour into a heatproof container to cool. It should thicken further as it cools.
• Pour caramel glaze over cooled cake and top with flaky sea salt.
  flaky sea salt